Dynamic laser speckle metrology with binarization of speckle patterns
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Dynamic laser speckle metrology with binarization of speckle patterns. / Stoykova, Elena; Nazarova, Dimana; Berberova, Nataliya; Gotchev, Atanas; Ivanov, Branimir; Mateev, Georgy.
19th International Conference and School on Quantum Electronics: Laser Physics and Applications. SPIE, 2017. 102260R (Proceedings of SPIE; Vuosikerta 10226).Tutkimustuotos › › vertaisarvioitu
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TY - GEN
T1 - Dynamic laser speckle metrology with binarization of speckle patterns
AU - Stoykova, Elena
AU - Nazarova, Dimana
AU - Berberova, Nataliya
AU - Gotchev, Atanas
AU - Ivanov, Branimir
AU - Mateev, Georgy
N1 - JUFOID=71479
PY - 2017
Y1 - 2017
N2 - Dynamic laser speckle analysis is non-destructive detection of physical or biological activity through statistical processing of speckle patterns on the surface of diffusely reflecting objects. This method is sensitive to microscopic changes of the surface over time and needs simple optical means. Advances in computers and 2D optical sensors forced development of pointwise algorithms. They rely on acquisition of a temporal sequence of correlated speckle images and generate activity data as a 2D spatial contour map of the estimate of a given statistical parameter. The most widely used pointwise estimates are the intensity-based estimates which compose each map entry from a time sequence of intensity values taken at one and the same pixel in the acquired speckle images. Accuracy of the pointwise approach is strongly affected by the signal-dependent nature of the speckle data when the spread of intensity fluctuations depends on the intensity itself. The latter leads to erroneous activity determination at non-uniform distribution of intensity in the laser beam for the non-normalized estimates. Normalization of the estimates, introduces errors. We propose to apply binarization to the acquired speckle images by comparing the intensity values in the temporal sequence for a given spatial point to the mean intensity value estimated for this point and to evaluate a polar correlation function. Efficiency of this new processing algorithm is checked both by simulation and experiment.
AB - Dynamic laser speckle analysis is non-destructive detection of physical or biological activity through statistical processing of speckle patterns on the surface of diffusely reflecting objects. This method is sensitive to microscopic changes of the surface over time and needs simple optical means. Advances in computers and 2D optical sensors forced development of pointwise algorithms. They rely on acquisition of a temporal sequence of correlated speckle images and generate activity data as a 2D spatial contour map of the estimate of a given statistical parameter. The most widely used pointwise estimates are the intensity-based estimates which compose each map entry from a time sequence of intensity values taken at one and the same pixel in the acquired speckle images. Accuracy of the pointwise approach is strongly affected by the signal-dependent nature of the speckle data when the spread of intensity fluctuations depends on the intensity itself. The latter leads to erroneous activity determination at non-uniform distribution of intensity in the laser beam for the non-normalized estimates. Normalization of the estimates, introduces errors. We propose to apply binarization to the acquired speckle images by comparing the intensity values in the temporal sequence for a given spatial point to the mean intensity value estimated for this point and to evaluate a polar correlation function. Efficiency of this new processing algorithm is checked both by simulation and experiment.
KW - Binary patterns
KW - Dynamic speckle
KW - Intensity-based algorithms
KW - Optical metrology
KW - Pointwise processing
U2 - 10.1117/12.2262330
DO - 10.1117/12.2262330
M3 - Conference contribution
T3 - Proceedings of SPIE
BT - 19th International Conference and School on Quantum Electronics: Laser Physics and Applications
PB - SPIE
ER -